The presence of dopants in an insulating or semiconducting matrix can increase the electrical conductivity of the matrix. Dopants can be introduced into a matrix or moved within a matrix to dynamically alter the electrical operation of an electrical device. In some circumstances, dopant shifting or movement can be induced by applying a current across a matrix. After application of the current, the location and characteristics of the dopants remain stable until the application of another current sufficient to displace the dopants. Typically, changing dopant configurations in a matrix results in changes to the electrical resistance of the device. Electrical devices that exhibit a memory of past electrical conditions through dopant-based changes in electrical resistance are known as memristive devices.